Stretching tool



AU8- 7, 1934- A. T. BERGsTRoM 1,969,115'

STRETCHING TOOL Patented Aug. 7, 1934 UNITED STATES STRETCHING TOOL Arthur T. Bergstrom, Chicago, Ill., assgnor to Signode Steel strapping Company, Chicago, Ill., a corporation of Delaware Application February s, 1932, sei-iai No. 591,609

1o claims. (c1.l esi- 51) stretch or tension the strap and are then secured together by suitable deformation or sealy ing. Diiiiculties have heretofore been experienced in the employment of such tools particularly in the matter of locating or maintaining the overlapping portions of the strap in accurate superposition. These difficulties have arisen from various causes among which may be mentioned carelessness of the operator in initially placing the straps in the tool, irregularities in the strap, and wear and deformation of the tool ptarticularly when high tension is applied to the s rap.

These difficulties have been particularly objectionable in combined stretchers and Sealers since the sealing position is fixed with respect to the other elements of the tool which operatively engage the strap, The present invention will accordingly be described in connection with such a combined tool although it is not intended to be limited thereto since it is highly advantageous in connection with stretchers with which a separate sealing tool is employed.

One of the objects of the invention is to provide an improved stretcher.

A further object of the invention is to provide a stretcher having movable guide means adapted to cooperate with the strap.

A further object of the invention is to provide a stretcher having a movable guide adapted to be brought into operative position by the actuation of the tool to engage the strap.

A further object of the invention is to provide a stretcher adapted to promptly draw the operators attention to initial misalignment of the superposed portions of the strap.

Other objects, advantages and capabilities of the invention will hereinafter appear from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a side elevational view of a combined stretcher and sealer showing a strap applied to a package and introduced into the tool for stretching Fig. 2 is a plan view of the tool;

Fig. 3 is a front elevation of the tool;

Fig. 4 is a side elevation of the oscillating frame of the tool;

Fig. 5 is a front elevation thereof; and

Fig. 6 is a detail view of the spindle which carries the oscillating frame, and the handle for rotating same.

Referring to the drawings, the tool comprises a main frame 10 which is provided with a pair 65 of bases or feet 11 and 12 which are adapted to rest on the surface of the package as shown in Fig. 1. The forward foot 11 over which the overlapping portions of the strap 13 extend is provided with an opening 14 so as to enable the 70 sealing jaws to engage said portions. The rear foot l2 is adapted to be placed upon the rear portion of the strap 13 which rises between the feet in the manner shown in Fig. 1.

On one side of the strap position the foot 11 75 rises into a vertical web 15 which extends rearwardly and merges with the main body 16 of the main frame 10. This main body 16 carries a forwardly extending web 17 which is located on the opposite side of the strap position and leaves an opening 17 above the foot 11 to allow entry and removal of the strap. The webs 15 and 17 are provided with openings 18 and 19 which provide bearings for the oscillating frame spindle. The main body 16 is provided with an abutment 20 and 85 the webs 15 and 17 are provided with abutments 21 and 22 which limit the oscillatory movements of the oscillating frame. A spring pressed pawl 23 is pivotally mounted between the webs 15 and 17, the function of which will be described hereinafter.

Below the openings 18 and 19 and in the strap position the foot 11 is provided with a hardened plug 24 the upper surface of which is provided with serrations and projects above the uppersurface of the foot in order to engage the lower of the superposed portions of the strap, and hold that portion in immovable relation to the plug and foot.

The oscillating frame 25 comprises a body 26 100 which is provided at its forward end with spaced parallel downwardly extending websl 27 and 28 which are provided with aligned openings 29 and 30. Above the webs 2'7 and 28 the body 26 of the 105 oscillating frame 25 is provided with an upwardly projecting stud 31, the upper end of which is reduced and threaded as shown in Figs. 4 and 5.

Rearwardly of the stud 31 the upper surface of the body 261s machined to provide a slide 32, and no a pair of longitudinal shoulders 33. Adjacent its rear end the body 26 is provided with upwardly directed bosses 34 and 35. The boss 34 is provided with a transverse opening 36. The rearmost boss 35 is provided on either side with conical openings 37. On its underside the body 26 is provided with an abutment 38 which is adapted to engage the abutment 20 on the main frame and above the openings 29 and 30 it is provided on each side with lateral shoulders or abutments 39 which are adapted to engage thevabutments 21 and 22 on the webs 15 and 17.

The lowermost portions of the webs 27 and 28 are concentric with the openings 29 and 30 and the web 28 is provided with a concentric flange 40 which is of somewhat greater radius than the edge of the web 27 as clearly shown in Figs. 4 and 5. A spring pressed pawl 41 is pivotally supported by a pin 42 between the webs 27 and 28 rearwardly of the openings 29 a'nd 30. This pawl is located in vertical alignment with respect to the pawl 23 and its function will be hereinafter described.

A handle 43 provided at its forward end with furcations 44 is pivotally connected to the oscillating frame 25 by means of a pin 45 which extends through openings in said furcations and through the opening 36 in the boss 34. The furcations 44 are provided with spring pressed plungers 46 which are adapted to enter the recesses 37 in the boss 35 to maintain the oscillating frame 25 and the handle 43 in rigid relationship during the normal stretching or tensioning operation as will hereinafter be described.

A forwardly directed anvil 47 is rigidly mounted on the stud 31, which also provides a pivot for the sealing jaws 48 which are located on each side of the anvil. 'Ihe jaws 48 carry outwardly and rearwardly extending arms 49 which are pivotally connected to links 50 which, in turn, are pivotally connected to a block 51 which slides on the slide 32. A link 52 is pivotally connected to the block 51 and to the furcations 44 of the handle 43 rearwardly of the pin 45. In order to.clear the boss 34 the link 52 is arched as shown in Fig. 1. 'I'he handle 43 is provided between the furcations 44 with a stud 53 which is adapted to engage the crown of the arched link 52 to limit the movement of the handle relative to the oscillating frame. in the counterclockwise direction as viewed in Figure 1. 'Ihe rear end of the link 52 is adapted to engage the oscillating frame 25 to limit relative movement in the opposite direction.

Two feed wheels 54 having serrated peripheries are mounted between the webs 27 and 28. These wheels are separated by a ratchet wheel 55 and the wheels 54 and 55 are rigidly secured together so as to act as a unit. They are provided with aligned central openings by means of whichthey are rotatably mounted upon the spindle 56. The spindle 56 has a cylindrical head 57 at one end which has a rotating flt in the opening 19 of the other web 17. At its outer end the head 57 is provided with a flange 58 which engages the outer face of the web 17. At its other end the spindle 56 is provided with a reduced portion 59 which is adapted toreceive a collar 60 similar to the head 57, this collar being secured to the spindle by means of a nut 6l screwed on the threaded end 0f the reduced portion 59. The collar 60 is adapted to have a rotating fit in the opening 18 of the web 15 and has a flange 62 which is adapted to bear against the outer face of said web. The head 57 is provided with a non-round projection 63 which is adapted to enter a corresponding recess in the hub of a handle 84. This handle is secured to the spindle by a bolt and engagement between the projection 63 and the recess in the handle insures the rigid mounting of the handle on the spindle.

Between the head 57 and the reduced portion 59, the spindle 56 is provided with an eccentric portion '66 upon which the oscillating frame 25 and the feed Wheel assembly are mounted, a bushing 67 being mounted on the eccentric portion 66 to serve as a bearing for the oscillating frame and the feed wheel assembly. The hub of the handle 64 is provided with shoulders 68 which are adapted to engage a pin 69 on the web 17 to limit the movement of the handle in either direction.

To assemble the tool, the feed wheel assembly is located between the webs 27 and 28 of the oscillating frame 25 so as to bring the central openings of the assembly into alignment with the openings 29 and 30, the pawl 41 being brought into cooperating relationship with the ratchet wheel 55 as shown in dotted lines in Fig. 1. 'I'he bushing 67 is then passed through the aligned openings. The webs 27 and 28 of the oscillating frame 25 are then passed between the webs 15 and 17 so as to bring'the bushing 67 into substantial alignment with the openings 18 and 19 with pawl 23 in cooperating relationship with the ratchet wheel 55. The collar 60 is removed from the spindle 56 which is then inserted through the opening 19 to enter the eccentric v1015 portion 66 into the bushing 67 and the head 57 into the opening 19. The collar 60 is then applied to the reduced end of the spindle in the opening 18 and the nut 61 is applied to the outer threaded portion thereof.

The operation of the tool is as follows: The strap 13 is pulled out from a source of supply and is passed in clockwise direction, as viewed in Fig. 1, around a box 70 or other package or assembly of packages which is or are to be bound. 115 The free end is located under the portion leading from the supply and the superposed portions held manually while the tool is slipped into operating position, both straps passing edgewise through opening 17 so as to lie above foot 11 and against 120 aligned guides 71 and 72 formed respectively on the front and rear of foot 11 and with foot 12 above the strap. In order to permit the positioning of the strap the gripper handle 64 is first moved into the position shown in Fig. 1 in 125 which condition the feed wheels are elevated so that the strap may be easily inserted between the wheels and the stationary gripper. When the strap is positioned the gripper handle is rotated in counterclockwise direction so as to 130 lower the oscillating frame 25 and feed wheels 54 so as to bring the latter into engagement with the upper surface ofthe top strap portion with sulcient force to enable the wheels to move the upper strap end upon the lower end thereof, and 135 to firmly engage the lower end of the toothed surface of plug 24. It is to be noted that this movement does not bring the feed wheels into their lowermost or maximum gripping position and that the tension, applied to the strap as here- 140 inafter described, will have the eiect oi' increasing the pressure of the feed wheels upon the superimposed strap portions and effectively prevent slippage between the feed wheels, and between the gripper plug -24 and adjacent strap 145 portions.

The counterclockwise movement of the handle 64 causes the ange 40 to project below the superimposed strap portions so as to provide an outer guide therefor.

The superimposed strap portions being thus engaged between the feed wheels 54 and the stud 24, the handle 43 is oscillated forwards and backwards. In the forward movement the pawl 23 holds the feed wheels stationary and the pawl 4l slips over the ratchet wheel 55, and the load is so light that the plungers 46 hold the handle rigid. In the backward movement the handle 43 applies tension to the strap through the pawl 41 and the feed wheels 54, the pawl 23 slipping over the teeth of the ratchet wheel 55. The upper portion of the strap is consequently moved to the left as viewed in Fig. 1, slipping over the lower portion of the strap which is held immovable by the stud 24. The load upon the handle 43 during the backward movement is consider- -able and during this movement the rear end of the link 52 bears upon the oscillating frame 25 and communicates the force thereto. During the above described tensioning operation the flange 40 being concentric with the pivotal mounting of the frame 25 always projects below the superimposed strap portions regardless of the oscillation of the frame and the strap is thereby forced to remain in the space between flange 40 and aligned guides 71 and 72 as the upper portion moves longitudinally relative to the lower portion.

When sufficient tension is applied to the strap la sleeve of known type may be applied to the superimposed portions of the strap above the opening 14 in the foot 11 or to the anvil 47 and the handle 43 is moved forwardly into its extreme forward position bringing the shoulders 39 of the oscillating frame 25 into abutting relation with the shoulders 21 and 22 on the webs 15 and 17, at which time the sealing jaws 48 are located on either side of the superimposed strap portions. Continued forward movement of the handle 43 causes the plungers 46 to withdrawn from the conical recesses 37 and the handle 43 moves relatively to the oscillating frame about its pivot 45. This relative movement between the handle 43 and the oscillating frame causes the block 51 to move upon the slide 32 and close the jaws 48 to make the seal, or joint between the superimposed strap portions including a sleeve if a sleeve is used.

The handle 43 is then moved rearwardly to open the jaws and release the sealed strap. The handle 64 is rotated in clockwise direction, as viewed in Fig. l, and the feed wheels are elevated, likewise the flange 40.- The tool is then moved laterally to remove the foot 11 from the underside of the strap and the strap is severed between the seal and the source of supply in any suitable manner.

' If the operator is careless in initially positioning the strap in the tool the flange 40 is brought into contact with the strap when the handle is rotated to lower the feed wheels. When the handle 43 is actuated to tension the strap the friction between the guide flange and the strap causes the handle to pivot on the oscillating frame and this apparent breaking of the tensioning handle at the initiation of the stretching operation draws the attention of the operator to the fact that the strap is not properly positioned and to the necessity for correcting the strap position. When the overlapping strap portions have been properly located in the tool and the gripper handle turned to lower the feed wheels upon theftop strap portion, flange 40 prevents the overlapping ends from getting out of alignment and out of proper position relative to the sealing mechanism when the same is moved to the joint producing location after the desired band tension is attained.A And the movements of the guide flange into and out of active position are effected automatically as the operator moves the tensioning wheels into and out of active position.

Although the invention has been .disclosed in connection with the detail of a specific embodiment thereof, it must be understood that such details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a stretching tool, in combination, a movable gripper adapted to engage a binder, means for actuating the gripper, and movable guide means movable with the gripper adapted to provide a guide for the binder. 2. In a stretching tool, in combination, gripping means adapted to be moved into and out of engagement with a binder, means for effecting such a movement, and a movable guide adapted to be actuated simultaneously by said'means.

3. In a stretching tool, in combination, means adapted to be actuated to engage a binder in operative relation, and a guide for the binder adapted to be actuated simultaneously therewith.

4. In a stretching tool, in combination, upper and lower means for engaging a strap therebetween,lateral means connecting said upper and lower means and constituting a guide for a binder, and means operative with the binder engaging means providing an outer guide therefor.

5. In a stretching tool, in combination, a frame, a feed wheel mounted therein, means for operating said feed wheel, means for raising and lowering said feed wheel, and means associated with said feed wheel and movable therewith adapted to provide a guide for the binder.

6. In a stretching tool, in combination, a frame, a feed wheel mounted therein, a reciprocable lever adapted to actuate said feed wheel, means for raising and lowering said feed wheel and the adjacent part of the lever, and a flange carried by said ,lever adapted to provide a guide for the binder.

7. In a stretching tool, in combination, a frame, a spindle supported from one side of said frame, a feed wheel and actuating lever mounted on an eccentric part of said spindle, means for rotating 'said spindle to bring the feed Wheel into operative relation with the frame, and means carried by the actuating lever adapted to be lowered into position on the outer side of the binder when the spindle is thus rotated.

8. In a stretching tool, in combination, a frame having a base, a feed wheel having an eccentric mounting on one side of the frame, an actuating lever mounted coaxially with said feed wheel and movable therewith, said feed wheel being capable of progressive rotation by reciprocation of the lever,.a handle adapted to be rotated to 1 the binder while the lever is reciprocated after the feed wheel is thus moved towards the base.

9. In a stretching tool, in combination, a mova-` ble gripper adapted to engage a binder, means for actuating the gripper, and means movable with the gripper adapted to engage the binder if same is improperly placed so as to prevent engagement of the gripper therewith.

10. In a stretching tool, in combination, gripping means adapted to be moved into and out .5 of engagement with a binder, means for effecting such movement, and a movable member adapted to be actuated simultaneously by said means, said T. BERGSTROM. 

